Golang Context.Versioned方法代码示例

// Delete removes a value with given key.
func (db *LevelDB) Delete(ctx storage.Context, tk storage.TKey) error {
	if db == nil {
		return fmt.Errorf("Can't call Delete on nil LevelDB")
	}
	if ctx == nil {
		return fmt.Errorf("Received nil context in Delete()")
	}
	wo := db.options.WriteOptions

	var err error
	key := ctx.ConstructKey(tk)
	if !ctx.Versioned() {
		dvid.StartCgo()
		err = db.ldb.Delete(wo, key)
		dvid.StopCgo()
	} else {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return fmt.Errorf("Non-versioned context that says it's versioned received in Delete(): %v", ctx)
		}
		tombstoneKey := vctx.TombstoneKey(tk)
		batch := db.NewBatch(vctx).(*goBatch)
		batch.WriteBatch.Delete(key)
		batch.WriteBatch.Put(tombstoneKey, dvid.EmptyValue())
		if err = batch.Commit(); err != nil {
			dvid.Criticalf("Error on batch commit of Delete: %v\n", err)
			err = fmt.Errorf("Error on batch commit of Delete: %v", err)
		}
	}

	return err
}

// SendKeysInRange sends a range of keys spanning (kStart, kEnd).  Values
// associated with the keys are not read.   If the keys are versioned, only keys
// in the ancestor path of the current context's version will be returned.
// End of range is marked by a nil key.
func (db *LevelDB) SendKeysInRange(ctx storage.Context, kStart, kEnd storage.TKey, kch storage.KeyChan) error {
	if db == nil {
		return fmt.Errorf("Can't call SendKeysInRange on nil LevelDB")
	}
	if ctx == nil {
		return fmt.Errorf("Received nil context in SendKeysInRange()")
	}
	ch := make(chan errorableKV)
	done := make(chan struct{})
	defer close(done)

	// Run the range query on a potentially versioned key in a goroutine.
	go func() {
		if !ctx.Versioned() {
			db.unversionedRange(ctx, kStart, kEnd, ch, done, true)
		} else {
			db.versionedRange(ctx.(storage.VersionedCtx), kStart, kEnd, ch, done, true)
		}
	}()

	// Consume the keys.
	for {
		result := <-ch
		if result.KeyValue == nil {
			kch <- nil
			return nil
		}
		if result.error != nil {
			kch <- nil
			return result.error
		}
		kch <- result.KeyValue.K
	}
}

// Put writes a value with given key.
func (db *LevelDB) Put(ctx storage.Context, tk storage.TKey, v []byte) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in Put()")
	}
	wo := db.options.WriteOptions

	var err error
	key := ctx.ConstructKey(tk)
	if !ctx.Versioned() {
		dvid.StartCgo()
		err = db.ldb.Put(wo, key, v)
		dvid.StopCgo()
	} else {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return fmt.Errorf("Non-versioned context that says it's versioned received in Put(): %v", ctx)
		}
		tombstoneKey := vctx.TombstoneKey(tk)
		batch := db.NewBatch(vctx).(*goBatch)
		batch.WriteBatch.Delete(tombstoneKey)
		batch.WriteBatch.Put(key, v)
		if err = batch.Commit(); err != nil {
			batch.Close()
			err = fmt.Errorf("Error on PUT: %v\n", err)
		}
	}

	storage.StoreKeyBytesWritten <- len(key)
	storage.StoreValueBytesWritten <- len(v)
	return err
}

// GetRange returns a range of values spanning (kStart, kEnd) keys.  These key-value
// pairs will be sorted in ascending key order.  If the keys are versioned, all key-value
// pairs for the particular version will be returned.
func (db *LevelDB) GetRange(ctx storage.Context, kStart, kEnd storage.TKey) ([]*storage.TKeyValue, error) {
	if ctx == nil {
		return nil, fmt.Errorf("Received nil context in GetRange()")
	}
	ch := make(chan errorableKV)

	// Run the range query on a potentially versioned key in a goroutine.
	go func() {
		if ctx == nil || !ctx.Versioned() {
			db.unversionedRange(ctx, kStart, kEnd, ch, false)
		} else {
			db.versionedRange(ctx.(storage.VersionedCtx), kStart, kEnd, ch, false)
		}
	}()

	// Consume the key-value pairs.
	values := []*storage.TKeyValue{}
	for {
		result := <-ch
		if result.KeyValue == nil {
			return values, nil
		}
		if result.error != nil {
			return nil, result.error
		}
		tk, err := ctx.TKeyFromKey(result.KeyValue.K)
		if err != nil {
			return nil, err
		}
		tkv := storage.TKeyValue{tk, result.KeyValue.V}
		values = append(values, &tkv)
	}
}

// Get returns a value given a key.
func (db *LevelDB) Get(ctx storage.Context, tk storage.TKey) ([]byte, error) {
	if ctx == nil {
		return nil, fmt.Errorf("Received nil context in Get()")
	}
	if ctx.Versioned() {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return nil, fmt.Errorf("Bad Get(): context is versioned but doesn't fulfill interface: %v", ctx)
		}

		// Get all versions of this key and return the most recent
		// log.Printf("  basholeveldb versioned get of key %v\n", k)
		values, err := db.getSingleKeyVersions(vctx, tk)
		// log.Printf("            got back %v\n", values)
		if err != nil {
			return nil, err
		}
		kv, err := vctx.VersionedKeyValue(values)
		// log.Printf("  after deversioning: %v\n", kv)
		if kv != nil {
			return kv.V, err
		}
		return nil, err
	} else {
		key := ctx.ConstructKey(tk)
		ro := db.options.ReadOptions
		// log.Printf("  basholeveldb unversioned get of key %v\n", key)
		dvid.StartCgo()
		v, err := db.ldb.Get(ro, key)
		dvid.StopCgo()
		storage.StoreValueBytesRead <- len(v)
		return v, err
	}
}

// KeysInRange returns a range of present keys spanning (kStart, kEnd).  Values
// associated with the keys are not read.   If the keys are versioned, only keys
// in the ancestor path of the current context's version will be returned.
func (db *LevelDB) KeysInRange(ctx storage.Context, kStart, kEnd storage.TKey) ([]storage.TKey, error) {
	if db == nil {
		return nil, fmt.Errorf("Can't call KeysInRange on nil LevelDB")
	}
	if ctx == nil {
		return nil, fmt.Errorf("Received nil context in KeysInRange()")
	}
	ch := make(chan errorableKV)

	// Run the range query on a potentially versioned key in a goroutine.
	go func() {
		if !ctx.Versioned() {
			db.unversionedRange(ctx, kStart, kEnd, ch, true)
		} else {
			db.versionedRange(ctx.(storage.VersionedCtx), kStart, kEnd, ch, true)
		}
	}()

	// Consume the keys.
	values := []storage.TKey{}
	for {
		result := <-ch
		if result.KeyValue == nil {
			return values, nil
		}
		if result.error != nil {
			return nil, result.error
		}
		tk, err := ctx.TKeyFromKey(result.KeyValue.K)
		if err != nil {
			return nil, err
		}
		values = append(values, tk)
	}
}

// Get returns a value given a key.
func (db *KVAutobus) Get(ctx storage.Context, tk storage.TKey) ([]byte, error) {
	if ctx == nil {
		return nil, fmt.Errorf("Received nil context in Get()")
	}
	if ctx.Versioned() {
		vctx, ok := ctx.(storage.VersionedCtx)
		if !ok {
			return nil, fmt.Errorf("Bad Get(): context is versioned but doesn't fulfill interface: %v", ctx)
		}

		// Get all versions of this key and return the most recent
		// log.Printf("  kvautobus versioned get of key %v\n", k)
		key := ctx.ConstructKey(tk)
		dvid.Infof("   Get on key: %s\n", hex.EncodeToString(key))
		values, err := db.getSingleKeyVersions(vctx, tk)
		// log.Printf("            got back %v\n", values)
		if err != nil {
			return nil, err
		}
		kv, err := vctx.VersionedKeyValue(values)
		// log.Printf("  after deversioning: %v\n", kv)
		if kv != nil {
			return kv.V, err
		}
		return nil, err
	} else {
		key := ctx.ConstructKey(tk)
		// log.Printf("  kvautobus unversioned get of key %v\n", key)
		v, err := db.RawGet(key)
		storage.StoreValueBytesRead <- len(v)
		return v, err
	}
}

// DeleteRange removes all key-value pairs with keys in the given range.
func (db *LevelDB) DeleteRange(ctx storage.Context, kStart, kEnd storage.TKey) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in DeleteRange()")
	}

	// For leveldb, we just iterate over keys in range and delete each one using batch.
	const BATCH_SIZE = 10000
	batch := db.NewBatch(ctx).(*goBatch)

	ch := make(chan errorableKV)

	// Run the keys-only range query in a goroutine.
	go func() {
		if ctx == nil || !ctx.Versioned() {
			db.unversionedRange(ctx, kStart, kEnd, ch, true)
		} else {
			db.versionedRange(ctx.(storage.VersionedCtx), kStart, kEnd, ch, true)
		}
	}()

	// Consume the key-value pairs.
	numKV := 0
	for {
		result := <-ch
		if result.KeyValue == nil {
			break
		}
		if result.error != nil {
			return result.error
		}

		// The key coming down channel is not index but full key, so no need to construct key using context.
		// If versioned, write a tombstone using current version id since we don't want to delete locked ancestors.
		// If unversioned, just delete.
		tk, err := ctx.TKeyFromKey(result.KeyValue.K)
		if err != nil {
			return err
		}
		batch.Delete(tk)

		if (numKV+1)%BATCH_SIZE == 0 {
			if err := batch.Commit(); err != nil {
				batch.Close()
				return fmt.Errorf("Error on batch DELETE at key-value pair %d: %v\n", numKV, err)
			}
			batch = db.NewBatch(ctx).(*goBatch)
		}
		numKV++
	}
	if numKV%BATCH_SIZE != 0 {
		if err := batch.Commit(); err != nil {
			batch.Close()
			return fmt.Errorf("Error on last batch DELETE: %v\n", err)
		}
	}
	dvid.Debugf("Deleted %d key-value pairs via delete range for %s.\n", numKV, ctx)
	return nil
}

// DeleteRange removes all key-value pairs with keys in the given range.  Versioned
// contexts cannot use immutable stores to delete ranges.
func (db *KVAutobus) DeleteRange(ctx storage.Context, kStart, kEnd storage.TKey) error {
	if ctx == nil {
		return fmt.Errorf("Received nil context in DeleteRange()")
	}
	if ctx.Versioned() {
		return fmt.Errorf("DeleteRange() not supported for versioned contexts in immutable store")
	}
	keyBeg := ctx.ConstructKey(kStart)
	keyEnd := ctx.ConstructKey(kEnd)
	return db.deleteRange(keyBeg, keyEnd)
}

// ProcessRange sends a range of key-value pairs to chunk handlers.  If the keys are versioned,
// only key-value pairs for kStart's version will be transmitted.  If f returns an error, the
// function is immediately terminated and returns an error.
func (db *LevelDB) ProcessRange(ctx storage.Context, kStart, kEnd storage.TKey, op *storage.ChunkOp, f storage.ChunkFunc) error {
	if db == nil {
		return fmt.Errorf("Can't call ProcessRange on nil LevelDB")
	}
	if ctx == nil {
		return fmt.Errorf("Received nil context in ProcessRange()")
	}
	ch := make(chan errorableKV)
	done := make(chan struct{})
	defer close(done)

	// Run the range query on a potentially versioned key in a goroutine.
	go func() {
		if ctx == nil || !ctx.Versioned() {
			db.unversionedRange(ctx, kStart, kEnd, ch, done, false)
		} else {
			db.versionedRange(ctx.(storage.VersionedCtx), kStart, kEnd, ch, done, false)
		}
	}()

	// Consume the key-value pairs.
	for {
		result := <-ch
		if result.KeyValue == nil {
			return nil
		}
		if result.error != nil {
			return result.error
		}
		if op != nil && op.Wg != nil {
			op.Wg.Add(1)
		}
		tk, err := storage.TKeyFromKey(result.KeyValue.K)
		if err != nil {
			return err
		}
		tkv := storage.TKeyValue{tk, result.KeyValue.V}
		chunk := &storage.Chunk{op, &tkv}
		if err := f(chunk); err != nil {
			return err
		}
	}
}